Asn React Native Reference Documentation

Asn

Current Version: 11.6.1

Chilkat.Asn

Load, inspect, build, edit, and encode ASN.1 structures in DER or XML form.

Chilkat.Asn represents an ASN.1 item and its optional child items. It can load ASN.1 from binary DER, encoded DER strings, files, or BinData; expose tags, tag values, primitive content, boolean and integer values, and child counts; build constructed structures such as SEQUENCE and SET; append common primitive types such as booleans, integers, big integers, bit strings, octets, OIDs, strings, times, null values, and context-specific items; convert ASN.1 to XML; reload from that XML form; and write the final structure back to DER.

Load DER data

Load ASN.1 from binary DER bytes, encoded text such as Base64 or hex, files, or existing BinData objects.

Inspect ASN.1 items

Read the item tag, tag value, constructed/primitive state, sub-item count, string content, boolean value, or integer value.

Build sequences and sets

Append constructed SEQUENCE and SET items, then add child ASN.1 values beneath them.

Append primitive values

Add booleans, integers, big integers, bit strings, octet strings, OIDs, strings, times, null values, and encoded byte content.

Context-specific tags

Add context-specific primitive or constructed items when working with ASN.1 formats that use tagged application-specific structures.

DER and XML conversion

Convert ASN.1 to XML for inspection or editing, load ASN.1 back from XML, and output the result as binary or encoded DER.

Common pattern: Load existing DER with LoadBinary, LoadEncoded, LoadBd, or LoadBinaryFile, inspect the tree with Tag, Constructed, NumSubItems, and GetSubItem, then extract primitive content or convert to XML with AsnToXml. To create ASN.1, start with a constructed item, append child values, and write the final DER with GetBinaryDer, GetEncodedDer, WriteBd, or WriteBinaryDer.

Object Creation

// npm install @chilkat/react-native react-native-nitro-modules
// (React Native 0.76+ with the New Architecture; then `pod install` for iOS.  The Chilkat
//  native library is downloaded and verified during the native build -- see the package README.)

import { Chilkat, Asn } from '@chilkat/react-native'

// Once per app start, before any other Chilkat call:
Chilkat.unlockBundle('Anything for 30-day trial')   // shorthand for new Global().unlockBundle(..)

const asn = new Asn()
// ... the native object is released when `asn` is garbage collected, or now with asn.dispose()
new Asn()

Creates the underlying native Chilkat object. Asn is a Nitro Module HybridObject: use it from the JavaScript thread only (it cannot be passed to a Worklet or another runtime). Every member is synchronous and blocks the JavaScript thread until Chilkat returns; a method that can take a while also exists as a ...Async twin returning a Promise, which runs the same call on a native worker thread so the UI keeps rendering. While such a call is pending, every other call on this object throws, except abort() and assigning onPercentDone / onProgressInfo.

dispose(): void

Releases the native object immediately instead of waiting for garbage collection (useful for a large BinData or an open socket). Calling it more than once is harmless; any other use of the object afterwards throws. An object with a pending ...Async call cannot be disposed until the promise settles.

Errors

A method that can fail throws a plain Error: a method whose only outcome is success or failure returns void and throws on failure; a method producing a string or an object returns it and throws where Chilkat would have returned null. The error's message is "Class.method(...): reason", where the reason is the last informative line of the object's lastErrorText, which holds the full Chilkat log of the failed call. A ...Async twin rejects its promise with the same Error instead of throwing. Properties never throw, and methods that answer a question (has..., is..., ...) return a plain boolean.

try {
  asn.someMethod(...)
} catch (e) {
  console.log((e as Error).message)   // Asn.someMethod(...): <reason>
  console.log(asn.lastErrorText)   // the full Chilkat log of the failed call
}

// The same call without blocking the JavaScript thread:
try {
  await asn.someMethodAsync(...)
} catch (e) {
  console.log((e as Error).message)   // Asn.someMethodAsync: <reason>
}

Properties

BoolValue
// read/write
boolValue: boolean
Introduced in version 9.5.0.49

The ASN.1 item's boolean value if it is a boolean item.

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Constructed
// read-only
readonly constructed: boolean
Introduced in version 9.5.0.49

true if this ASN.1 item is a constructed item. Sequence and Set items are constructed and can contain sub-items. All other tags (boolean, integer, octets, utf8String, etc.) are primitive (non-constructed).

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ContentStr
// read/write
contentStr: string
Introduced in version 9.5.0.49

The ASN.1 item's content if it is an ASN.1 string type (such as Utf8String, BmpString, PrintableString, VisibleString, T61String, IA5String, NumericString, or UniversalString).

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DebugLogFilePath
// read/write
debugLogFilePath: string

If set to a file path, this property logs the LastErrorText of each Chilkat method or property call to the specified file. This logging helps identify the context and history of Chilkat calls leading up to any crash or hang, aiding in debugging.

Enabling the VerboseLogging property provides more detailed information. This property is mainly used for debugging rare instances where a Chilkat method call causes a hang or crash, which should generally not happen.

Possible causes of hangs include:

  • A timeout property set to 0, indicating an infinite timeout.
  • A hang occurring within an event callback in the application code.
  • An internal bug in the Chilkat code causing the hang.

More Information and Examples
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IntValue
// read/write
intValue: number
Introduced in version 9.5.0.49

The ASN.1 item's integer value if it is a small integer item.

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LastErrorHtml
// read-only
readonly lastErrorHtml: string

Provides HTML-formatted information about the last called method or property. If a method call fails or behaves unexpectedly, check this property for details. Note that information is available regardless of the method call's success.

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LastErrorText
// read-only
readonly lastErrorText: string

Provides plain text information about the last called method or property. If a method call fails or behaves unexpectedly, check this property for details. Note that information is available regardless of the method call's success.

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LastErrorXml
// read-only
readonly lastErrorXml: string

Provides XML-formatted information about the last called method or property. If a method call fails or behaves unexpectedly, check this property for details. Note that information is available regardless of the method call's success.

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LastMethodSuccess
// read/write
lastMethodSuccess: boolean

Indicates the success or failure of the most recent method call: true means success, false means failure. This property remains unchanged by property setters or getters. This method is present to address challenges in checking for null or Nothing returns in certain programming languages. Note: This property does not apply to methods that return integer values or to boolean-returning methods where the boolean does not indicate success or failure.

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NumSubItems
// read-only
readonly numSubItems: number
Introduced in version 9.5.0.49

The number of sub-items contained within this ASN.1 item. Only constructed items, such as Sequence and Set will contain sub-iitems. Primitive items such as OIDs, octet strings, integers, etc. will never contain sub-items.

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Tag
// read-only
readonly tag: string
Introduced in version 9.5.0.49

The ASN.1 item's tag as a descriptive string. Possible values are:

boolean
integer
bitString
octets
null
oid
utf8String
relativeOid
sequence
set
numericString
printableString
t61String
ia5String
utcTime
bmpString

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TagValue
// read-only
readonly tagValue: number
Introduced in version 9.5.0.49

The ASN.1 item's tag as a integer value. The integer values for possible tags are as follows:

boolean (1)
integer (2)
bitString (3)
octets (4)
null (5)
oid (6)
utf8String (12)
relativeOid (13)
sequence (16)
set (17)
numericString (18)
printableString (19)
t61String (20)
ia5String (22)
utcTime (23)
bmpString (30)

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VerboseLogging
// read/write
verboseLogging: boolean

If set to true, then the contents of LastErrorText (or LastErrorXml, or LastErrorHtml) may contain more verbose information. The default value is false. Verbose logging should only be used for debugging. The potentially large quantity of logged information may adversely affect peformance.

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Version
// read-only
readonly version: string

Version of the component/library, such as "10.1.0"

More Information and Examples
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Methods

AppendBigInt
appendBigInt(encodedBytes: string, encoding: string): void
Introduced in version 9.5.0.49

Appends an ASN.1 integer, but one that is a big (huge) integer that is too large to be represented by an integer variable. The bytes composing the integer are passed in encoded string format (such as base64, hex, etc.). The byte order must be big-endian. The encoding may be any of the following encodings: Base64, Hex, Base58, modBase64, Base32, UU, QP (for quoted-printable), URL (for url-encoding), Q, B, url_oath, url_rfc1738, url_rfc2396, and url_rfc3986. The encoding name is case insensitive (for example, both Base64 and base64 are treated the same).

Returns normally on success; throws an Error on failure.

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AppendBits
appendBits(encodedBytes: string, encoding: string): void
Introduced in version 9.5.0.49

Appends an ASN.1 bit string to the caller's sub-items. The bytes containing the bits are passed in encoded string format (such as base64, hex, etc.). The byte order must be big-endian (MSB first). The encoding may be any of the following encodings: Base64, Hex, Base58, modBase64, Base32, UU, QP (for quoted-printable), URL (for url-encoding), Q, B, url_oath, url_rfc1738, url_rfc2396, and url_rfc3986. The encoding name is case insensitive (for example, both Base64 and base64 are treated the same).

Returns normally on success; throws an Error on failure.

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AppendBool
appendBool(value: boolean): void
Introduced in version 9.5.0.49

Appends an ASN.1 boolean item to the caller's sub-items. Items may only be appended to constructed data types such as Sequence and Set.

Returns normally on success; throws an Error on failure.

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AppendContextConstructed
appendContextConstructed(tag: number): void
Introduced in version 9.5.0.50

Appends an ASN.1 context-specific constructed item to the caller's sub-items.

Returns normally on success; throws an Error on failure.

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AppendContextPrimitive
appendContextPrimitive(tag: number, encodedBytes: string, encoding: string): void
Introduced in version 9.5.0.50

Appends an ASN.1 context-specific primitive item to the caller's sub-items. The bytes are passed in encoded string format (such as base64, hex, etc.). The encoding may be any of the following encodings: Base64, Hex, Base58, modBase64, Base32, UU, QP (for quoted-printable), URL (for url-encoding), Q, B, url_oath, url_rfc1738, url_rfc2396, and url_rfc3986. The encoding name is case insensitive (for example, both Base64 and base64 are treated the same).

Returns normally on success; throws an Error on failure.

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AppendInt
appendInt(value: number): void
Introduced in version 9.5.0.49

Appends an ASN.1 integer item to the caller's sub-items. Items may only be appended to constructed data types such as Sequence and Set.

Returns normally on success; throws an Error on failure.

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AppendNull
appendNull(): void
Introduced in version 9.5.0.49

Appends an ASN.1 null item to the caller's sub-items. Items may only be appended to constructed data types such as Sequence and Set.

Returns normally on success; throws an Error on failure.

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AppendOctets
appendOctets(encodedBytes: string, encoding: string): void
Introduced in version 9.5.0.49

Appends an ASN.1 octet string to the caller's sub-items. The bytes are passed in encoded string format (such as base64, hex, etc.). The encoding may be any of the following encodings: Base64, Hex, Base58, modBase64, Base32, UU, QP (for quoted-printable), URL (for url-encoding), Q, B, url_oath, url_rfc1738, url_rfc2396, and url_rfc3986. The encoding name is case insensitive (for example, both Base64 and base64 are treated the same).

Returns normally on success; throws an Error on failure.

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AppendOid
appendOid(oid: string): void
Introduced in version 9.5.0.49

Appends an ASN.1 OID (object identifier) to the caller's sub-items. The OID is passed in string form, such as 1.2.840.113549.1.9.1.

Returns normally on success; throws an Error on failure.

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AppendSequence
appendSequence(): void
Introduced in version 9.5.0.49

Appends an ASN.1 sequence item to the caller's sub-items.

Returns normally on success; throws an Error on failure.

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AppendSequence2
appendSequence2(): void
Introduced in version 9.5.0.50

Appends an ASN.1 sequence item to the caller's sub-items, and updates the internal reference to point to the newly appended sequence item.

Returns normally on success; throws an Error on failure.

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AppendSequenceR
appendSequenceR(): Asn
Introduced in version 9.5.0.50

Appends an ASN.1 sequence item to the caller's sub-items, and returns the newly appended sequence item.

Throws an Error on failure (where the description says null is returned, the method throws instead).

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AppendSet
appendSet(): void
Introduced in version 9.5.0.49

Appends an ASN.1 set item to the caller's sub-items.

Returns normally on success; throws an Error on failure.

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AppendSet2
appendSet2(): void
Introduced in version 9.5.0.50

Appends an ASN.1 set item to the caller's sub-items, and updates the internal reference to point to the newly appended set item.

Returns normally on success; throws an Error on failure.

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AppendSetR
appendSetR(): Asn
Introduced in version 9.5.0.50

Appends an ASN.1 set item to the caller's sub-items, and returns the newly appended set item.

Throws an Error on failure (where the description says null is returned, the method throws instead).

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AppendString
appendString(strType: string, value: string): void
Introduced in version 9.5.0.49

Appends a string item to the caller's sub-items. The strType specifies the type of string to be added. It may be utf8, ia5, t61, printable, visible, numeric, universal, or bmp. The value must conform to the ASN.1 restrictions imposed for a given string type. The utf8, bmp, and universal types have no restrictions on what characters are allowed. In general, unless a specific type of string is required, choose the utf8 type.

Returns normally on success; throws an Error on failure.

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AppendTime
appendTime(timeFormat: string, dateTimeStr: string): void
Introduced in version 9.5.0.49

Appends a UTCTime item to the caller's sub-items. The timeFormat specifies the format of the dateTimeStr. It should be set to utc. (In the future, this method will be expanded to append GeneralizedTime items by using generalized for timeFormat.) To append the current date/time, set dateTimeStr equal to the empty string or the keyword now. Otherwise, the dateTimeStr should be in the UTC time format YYMMDDhhmm[ss]Z or YYMMDDhhmm[ss](+|-)hhmm.

Returns normally on success; throws an Error on failure.

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AsnToXml
asnToXml(): string
Introduced in version 9.5.0.49

Converts ASN.1 to XML and returns the XML string.

Throws an Error on failure (where the description says null is returned, the method throws instead).

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DeleteSubItem
deleteSubItem(index: number): void
Introduced in version 9.5.0.49

Discards the Nth sub-item. (The 1st sub-item is at index 0.)

Returns normally on success; throws an Error on failure.

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GetEncodedContent
getEncodedContent(encoding: string): string
Introduced in version 9.5.0.49

Returns the content of the ASN.1 item in encoded string form. The encoding may be any of the following encodings: Base64, Hex, Base58, modBase64, Base32, UU, QP (for quoted-printable), URL (for url-encoding), Q, B, url_oath, url_rfc1738, url_rfc2396, and url_rfc3986. The encoding name is case insensitive (for example, both Base64 and base64 are treated the same).

Throws an Error on failure (where the description says null is returned, the method throws instead).

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GetEncodedDer
getEncodedDer(encoding: string): string
Introduced in version 9.5.0.49

Returns the binary DER in encoded string form. The encoding indicates the encoding and can be base64, hex, uu, quoted-printable, base32, or modbase64.

Throws an Error on failure (where the description says null is returned, the method throws instead).

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GetLastSubItem
getLastSubItem(): Asn
Introduced in version 9.5.0.49

Returns the last ASN.1 sub-item. This method can be called immediately after any Append* method to access the appended item.

Throws an Error on failure (where the description says null is returned, the method throws instead).

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GetSubItem
getSubItem(index: number): Asn
Introduced in version 9.5.0.49

Returns the Nth ASN.1 sub-item. The 1st sub-item is at index 0.

Throws an Error on failure (where the description says null is returned, the method throws instead).

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LoadAsnXml
loadAsnXml(xmlStr: string): void
Introduced in version 9.5.0.49

Loads ASN.1 from the XML representation (such as that created by the AsnToXml method).

Returns normally on success; throws an Error on failure.

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LoadBd
loadBd(bd: BinData): void
Introduced in version 9.5.0.77

Loads ASN.1 from the binary DER contained in bd.

Returns normally on success; throws an Error on failure.

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LoadBinaryFile
loadBinaryFile(path: string): void
Introduced in version 9.5.0.49

Loads ASN.1 from a binary DER file.

Returns normally on success; throws an Error on failure.

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LoadEncoded
loadEncoded(asnContent: string, encoding: string): void
Introduced in version 9.5.0.49

Loads ASN.1 from an encoded string. The encoding can be base64, hex, uu, quoted-printable, base32, or modbase64.

Returns normally on success; throws an Error on failure.

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SetEncodedContent
setEncodedContent(encodedBytes: string, encoding: string): void
Introduced in version 9.5.0.49

Sets the content of this primitive ASN.1 item. The encoding may be any of the following encodings: Base64, Hex, Base58, modBase64, Base32, UU, QP (for quoted-printable), URL (for url-encoding), Q, B, url_oath, url_rfc1738, url_rfc2396, and url_rfc3986. The encoding name is case insensitive (for example, both Base64 and base64 are treated the same).

Returns normally on success; throws an Error on failure.

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WriteBd
writeBd(bd: BinData): void
Introduced in version 9.5.0.77

Appends the ASN.1 in binary DER format to bd.

Returns normally on success; throws an Error on failure.

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WriteBinaryDer
writeBinaryDer(path: string): void
Introduced in version 9.5.0.49

Writes the ASN.1 in binary DER form to a file.

Returns normally on success; throws an Error on failure.

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